French chemist who isolated the major components of air, disproved the phlogiston theory by determining the role of oxygen in combustion, and devised a system of chemical nomenclature. Lavoisier was executed during the Reign of Terror.
French chemist who is regarded as one of the founders of modern chemistry. In 1778 he discovered that air consists of a mixture of two gases, which he called oxygen and nitrogen. Lavoisier also discovered the law of conservation of mass and devised the modern method of naming chemical compounds. His wife Marie (1758–1836) assisted him with his laboratory work and translated a number of important chemistry texts.